Stereotypic movement disorder
|Stereotypic movement disorder|
|Classification and external resources|
Stereotypic movement disorder (SMD) is a motor disorder with onset in childhood involving repetitive, nonfunctional motor behavior (e.g., hand waving or head banging), that markedly interferes with normal activities or results in bodily injury. The behavior must not be due to the direct effects of a substance or another medical condition. The cause of this disorder is not known.
- Classification 1
- Signs and symptoms 2
- Differential diagnosis 3.1
- Prognosis 4
- Epidemiology 5
- References 6
- Further reading 7
Stereotypic movement disorder is classified in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a motor disorder, in the category of neurodevelopmental disorders.
Signs and symptoms
Common repetitive movements of SMD include head banging, arm waving, hand shaking, rocking and rhythmic movements, self-biting, self-hitting, skin-picking; other stereotypies are thumb-sucking, nail biting, trichotillomania, bruxism and abnormal running or skipping.
Stereotyped movements are common in infants and young children; if the child is not distressed by movements and daily activities are not impaired, diagnosis is not warranted. When stereotyped behaviors cause significant impairment in functioning, an evaluation for stereotypic movement disorder is warranted. There are no specific tests for diagnosing this disorder, although some tests may be ordered to rule out other conditions. SMD may occur with Lesch-Nyhan syndrome, intellectual disability, and fetal alcohol exposure or as a result of amphetamine intoxication.
When diagnosing Stereotypic movement disorder, DSM-5 calls for specification of:
- with or without self-injurious behavior;
- association with another known medical condition or environmental factor;
- severity (mild, moderate or severe).
Other conditions which feature repetitive behaviors in the differential diagnosis include autism spectrum disorders, obsessive–compulsive disorder, tic disorders (e.g., Tourette syndrome), and other conditions including dyskinesias.
Stereotypic movement disorder is often misdiagnosed as tics or Tourette syndrome (TS). Unlike the tics of TS, which tend to appear around age six or seven, repetitive movements typically start before age three, are more bilateral than tics, and consist of intense patterns of movement for longer runs than tics. Tics are less likely to be stimulated by excitement. Children with stereotypic movement disorder do not always report being bothered by the movements as a child with tics might.
Prognosis depends on the severity of the disorder. Recognizing symptoms early can help reduce the risk of self-injury, which can be lessened with medications. Stereotypic movement disorder due to head trauma may be permanent.
Although not necessary for the diagnosis, individuals with intellectual disability are at higher risk for SMD. It is more common in boys, and can occur at any age.
- American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (Fifth ed.). Arlington, VA: American Psychiatric Publishing. pp. 77–80.
- "Stereotypic movement disorder". MedlinePlus. June 15, 2012. Retrieved October 6, 2013.
- Ellis CR, Pataki C. "Childhood Habit Behaviors and Stereotypic Movement Disorder". Medscape. Retrieved October 6, 2013.
- Singer HS. Motor stereotypies (PDF). Semin Pediatr Neurol. 2009 Jun;16(2):77–81. PMID 19501335 doi:10.1016/j.spen.2009.03.008
- Ellis CR, Pataki C. "Background: Childhood Habit Behaviors and Stereotypic Movement Disorder". Medscape. Retrieved October 6, 2013.
- Freeman, R (December 10, 2010). "Tourette's Syndrome: minimizing confusion". Retrieved October 6, 2013. A blog by Roger Freeman, MD, clinical head of the Neuropsychiatry Clinic, British Columbia's Children's Hospital, professional advisory board member of the Tourette Syndrome Foundation of Canada, and former member of the Tourette Syndrome Association Medical Advisory Board.
- Freeman RD, Soltanifar A, Baer S. Stereotypic movement disorder: easily missed (PDF). Dev Med Child Neurol. 2010 Aug;52(8):733–8. PMID 20187883doi:10.1111/j.1469-8749.2010.03627.x